After making a deal with the King of Hell Crowley to give Sam and Dean Winchester the wrong blood, Leviathan leader Dick Roman anticipated Crowley betraying him and so decided to take precautions. Dick had his assistant Susan bring him the arm of the original human Richard Roman and had several Leviathans touch it and take on his form to confuse the Winchesters.
During the meeting between Dick and the Leviathan Delegates, the Winchesters arrived and witnessed three different Dick Romans on SucroCorp's security cameras and were unable to tell which one was the real Dick Roman. After retreating to Rufus's cabin, the Winchesters tried without success to find a way to bypass the disguise. Finally, the demon Meg revealed that Castiel, as the original vessel for all of the Leviathans, could tell them apart no matter what form they were in and would thus be able to tell which was the real Dick and which were the imposters.
During the following battle, at least one member of the security detail was encountered by Dean and Castiel, sitting at a table in the conference room and going through paperwork. After a quick look, Castiel determined that it was not Dick and the two carried on until they finally located the real Dick in the lab. When confronted by Dean and Castiel, Dick attempted to confuse Dean by asking if Dean could really tell if it was him or not, but Dean informed him that Castiel could.
Following Dick's death, it is unknown what happened to these Leviathans. It is likely that they were dispatched by the "small army" of demons that Crowley brought in to deal with the remaining Leviathans at SucroCorp when Dick was killed.